Lockout procedures are put in place to ensure that a piece of equipment cannot be turned on, pressurized or switched on accidentally while an employee is working on it. These safety procedures typically involve one or more personal locks (padlocks), typically bearing the worker's name, and to which only the worker has the key. The lock needs to be removed to allow operation of the equipment. The piece of equipment can thus be said to be locked-out.
A lockout procedure for a given piece of machinery can require one or more lockout devices such as gate valve lockout devices, breaker switch lockout devices, safety clasp lockout devices, which are used on the piece of equipment and to which locks are attached to prevent removal.
In a single lockout, the worker checks the number and the description of the equipment and then attaches his or her personal lock as well as an instruction label.
In a multiple lockout, the person in charge of the lockout obtains the lockout cards from the department. The person in charge of the lockout follows the instructions on the lockout card, using a lockout box and the departmental locks. Once the lockout is completed, the person in charge of the lockout places an instruction label on the equipment or power source that was locked out. This person also signs and dates the lockout card, thus authorizing the workers to carry out the work, places the keys from all the departmental locks in the lockout box and attaches a departmental lock and an instruction label to the equipment. The lockout card is stored with the lockout box. The lockout box is placed in the predetermined lockout area. Each worker directly involved reads the lockout card and, if he judges it to be satisfactory for his own safety, attaches his personal lock to the lockout box. In case of a reasonable doubt, any worker must personally check the locked out (sealed) articles, before placing his lock on the lockout box. The person in charge of the lockout is the last to remove his lock or the departmental lock, after checking that the workers have completed their job and have removed their individual locks. When all the locks have been removed, the lockout card is returned to the head or his representative of the department concerned, indicating that the work is completed.
The lockout box typically consisted of a box having a chest-like configuration which had certain limitations. There remained room for improvement.